System and method for manufacturing an ignition coil

ABSTRACT

A coil winding system includes a scale configured to determine a weight of new spool of wire destined for inclusion in the system. The scale is electrically coupled to a controller portion of the system to automatically provide the determined weight. The controller is configured to automatically receive the weight information and associate it with a particular spindle. The controller calculates the maximum number of complete winding cycles possible, based on the weight, and stops winding after such maximum number has been completed.

BACKGROUND OF THE INVENTION

[0001] 1. Technical Field

[0002] The present invention relates generally to the field of engine ignition coils, and, more particularly, to a system and method for manufacturing an ignition coil.

[0003] 2. Description of the Related Art

[0004] It is known to use an automated winding system for the manufacture of ignition coils wherein the system has a plurality of spindles for receiving empty coil spools or bobbins, as seen by reference to U.S. Pat. No. 5,950,956 issued to Yukitake. Yukitake discloses an ignition coil winding machine capable of simultaneously forming a plurality of engine ignition coils. The machine has a driver for rotating a shaft on which a coil bobbin is disposed, all under the control of a controller. The machine further includes a tensioning device in between a wire spool (containing wire destined for being wound on the bobbins) and a nozzle. The nozzle reciprocates in the coil winding direction, thereby laying out the wire on the bobbin according to a method specified in the Yukitake.

[0005] Generally, in the operation of the machine of the type disclosed in Yukitake, when a wire spool runs out of wire, the machine will decelerate the rotation of the corresponding spindle to a stop. An operator removes the incompletely wound ignition coil and restarts the machine in order to complete the winding cycle on the other spindles. At the conclusion of the cycle, the operator will rethread a new spool of wire through the machine to replace the spool that ran out of wire. There are several problems, however, with the foregoing process.

[0006] First, the part (i.e., the incompletely wound ignition coil) must be scrapped since it is incompletely wound.

[0007] Second, pieces of wire can contaminate other coils. During deceleration, the free end of the wire is thrown around the machine until the machine stops and pieces thereof may fall on or into the surrounding coils that are in the process of being made. If the pieces are not detected by the operator and removed (e.g., vacuumed out), the affected ignition coil may fail.

[0008] Third, the operator must perform work on the machine twice for each wire spool change, namely, (i) stopping the machine to remove the incompletely wound coil, and then, after the winding cycle has been completed, (ii) stopping the machine again to rethread the machine, as described above. Alternatively, the operator can let the machine continue running even after the wire spool has run out of wire; however, this permits the spindle to whip the wire end around and greatly increases the probability that pieces of wire will break off and be cast around, causing the problems noted above.

[0009] One approach taken in the art to improve on the foregoing process involves weighing a new wire spool destined for replacement of the spool that just ran out of wire, and manually (i.e., via the operator) inputting both the weight and the corresponding spindle number into the winding machine controller. The “new” wire is tied to the remaining wire and is pulled through the machine to thread it. The controller calculates the number of empty ignition coil spools that can be wound from the wire on the wire spool based on the entered weight. The winding machine controller in this approach is configured to: (i) give an alarm a predetermined number of cycles before the wire spool is expected to run out of wire to notify the operator that the wire spool was low on wire, and (ii) shut down the winding operation when the calculated number of winding cycles has been completed. Improvements include eliminating free wire pieces, reducing part scrap, and reducing the number of times an operator is involved per-spool-change to one. However, the foregoing improvements are achieved only if the operator correctly enters both the accurate weight, and the correct spindle number. Operator error thus continues to be a problem.

[0010] There is therefore a need for an improved winding system that minimizes or eliminates one or more of the problems as set forth above.

SUMMARY OF THE INVENTION

[0011] One advantage of the present invention derives from directly providing the weight of the wire spool, and the correct spindle number to the winding system, thereby substantially eliminating the likelihood of operator error. Elimination of free wire pieces, part scrap, and reducing the number of times an operator has to work on the machine per spool-change are all achieved.

[0012] In accordance with the present invention, a method is provided for winding a bobbin to form a coil. The method includes the step of determining a weight of a spool containing wire and electronically providing the determined weight to a winding system configured to use the determined weight to control winding of the bobbin. Accordingly, operator involvement in the transfer of such information (i.e., weight and spindle number) is eliminated, thereby eliminating the likelihood of operator error.

[0013] In a preferred embodiment, optionally, the method further includes associating the determined weight with one of a plurality of spindles of the winding system. Next, determining a number of complete winding cycles that can be performed based on the determined weight, each winding cycle corresponding to a fall winding of a coil bobbin with wire from the wire spool. Finally, discontinuing the sequence of complete winding cycles when the number of completed winding cycles equals the determined number that was calculated based on weight.

[0014] In another embodiment, a system for winding a bobbin is also presented.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Additional objects and advantages of the present invention will be more readily apparent from the following detailed description of preferred embodiments thereof, when taken together with the accompanying drawings in which:

[0016]FIG. 1 is a simplified block diagram view of a winding system having an electrically connected weight scale according to the present invention;

[0017]FIG. 2 is a partial, perspective view showing the winding system of FIG. 1 in a multi-spindle configuration; and

[0018]FIG. 3 is a flowchart diagram corresponding to the methodology of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Referring now to the drawings wherein like reference numerals are used to identify identical components in the various views, FIG. 1 shows a winding system 10 in accordance with the present invention. Winding system 10 includes a main controller 12, a dereeler assembly 14, and a drive portion 16 that includes one or more spindles 18 and corresponding number of nozzles 20. The basic winding system 10 (exclusive of a scale 30 to be described below) is generally of a conventional nature and may be any one of a number of commercially available systems. For example, a multi-spindle coil winding machine (exclusive of scale 30 and the accompanying connection, and interface software functionality to be described in detail hereinafter), may be obtained from Prosys Industries, Inc., Plymouth, Mich., USA. FIG. 1 further illustrates an ignition coil bobbin 22, a wire feed assembly 24 comprising wire 26 contained on spool 28. In alternate embodiments, the winding system 10 may comprise a single-spindle winder, a fly type winder (i.e., post for receiving bobbin does not move but winding head does), an insertion type winder, an armature type winder, and a yolk type winder.

[0020]FIG. 2 illustrates the drive portion 16 of machine winding system 10 in greater detail. As shown in FIG. 2, winding system 10 is of the type that is capable of simultaneously winding a plurality of bobbins 22 ₁, 22 ₂, . . . , 22 _(i) respectively mounted to spindles 18 ₁, 18 ₂, . . . , 18 _(i). Corresponding parallel structure such as nozzles 20 _(i), 20 ₂, . . . , 20 _(i), and dereeler assemblies 14 ₁, 14 ₂, . . . , 14 _(i) are operative to feed respective runs of wire 26 ₁, 26 ₂ . . . 26 _(i) for winding ignition coils.

[0021] With continued reference to FIG. 1, generally, wire 26 is drawn from spool 28 and is fed through dereeler 14, which may provide a tensioning and/or take-up function relative to the wire 26. Drive portion 16 is configured, generally, to rotate spindle 18 containing bobbin 22, and, further, to reciprocate nozzle 20 over a preprogrammed axial length over bobbin 22. There are a plurality of winding schemes known to those of ordinary skill in the art, which will not be described herein in any detail. Drive portion 16 operates in accordance with control signals received from and generated by controller 12. Nozzle 20 can be moved by drive portion 16 axially with respect to spindle 18, as well as being rotated, all as known to one of ordinary skill in the art. Through the foregoing, a variety of coils having desired winding patterns may be made. In a preferred embodiment, the coil may be a primary or secondary coil of an ignition coil for an engine, such as an automotive engine. In alternate embodiments, the coil may be windings used in motors such as windshield wiper motors, solenoids, generators, alternators, speedometer dials, high-voltage yokes (i.e., for picture tubes), and inducators. Types of windings include layered, progressive (wedge, bank, pilgrim), segment, yoke, bobbin, paper (paper sectioned), toroidal, motor, insertion winding, stator winding, and bondable wire type winding. The wound element defining the coil may also include thread, string or nylon cord, in addition to wire.

[0022] Digital scale 30 is configured to determine a weight of a spool 28 containing wire 26 and generate a weight indicative signal representative of the determined weight, and provide such signal automatically to winding system 10, in particular, controller 12. The scale 30 includes an interface that is compatible with controller 12. The weight information is transferred through this interface. Digital scale 30 may comprise conventional components well known to those of ordinary skill in the art, and may be, for example, a Digimatix, Inc. Model No. D.C. 130. It should be understood, however, that other scales may be used and remain within the spirit and scope of the present invention.

[0023]FIG. 3 is a simplified flowchart diagram illustrating a method in accordance with the present invention. As used herein, a “cycle” is the process of completely winding one bobbin, or, if simultaneously winding multiple bobbins (a multi-spindle system), then completely winding the several bobbins. It should be appreciated that the process to be described hereinafter in connection with FIG. 3, applicable to the control of one spindle, may occur in parallel for each one of a plurality of spindles included in winding system 10. Thus, while the process for one spindle may not require the machine to stop (i.e., there is still wire left on the spool), the same process, occurring in parallel for another spindle may nonetheless cause the machine to stop after a cycle to accomplish a spool change

[0024] With continued reference to FIG. 3, the method begins in step 32, wherein a new spool of wire is needed for winding system 10 (or, at the beginning of a work day or the like where new wire spools are put on for all of the spindles of the winding system 10). In the case where winding system 10 has been operating, and an existing spool 28 has been used to complete as many cycles as possible, an operator obtains a new wire spool and places it on scale 30, which automatically determines its weight. In a preferred embodiment, controller 12 has been configured to recognize when a particular spool associated with a spindle is out of wire (or, when the wire spool has been used for as many winding cycles as possible without actually running out of wire, which is undesirable as described above). In such an embodiment, controller 12 generates a prompt to the operator, in order to confirm the spindle number in connection with which the new wire spool 28 is needed (e.g., “Is spindle #1 the correct spindle that is out of wire? If yes, then press ENTER.”). The controller 12 carries forward the knowledge it has regarding what spool/spindle is low on wire from the previous iteration of the process (steps 32-44), which determine the maximum number of cycles, and a running counter of the number of completed cycles since the last wire spool was installed.

[0025] In step 34, the scale 30, in electrical communication with controller 12, electronically, automatically, provides the determined weight thereto via a compatible interface for subsequent use. As indicated above, the controller 12, via the preceding dialogue with the operator, is configured with the identity of the spindle number.

[0026] In step 36, controller 12 is configured to associate the weight provided from scale 30 (determined in step 32) with the selected one of the plurality of spindles on the winding system 10. The process proceeds to step 38.

[0027] In step 38, the controller 12 determines the number of complete winding cycles that can be performed using the wire 26 on the new winding spool 28, based on the weight determined in step 32. Performance of this step may further include using predetermined data corresponding to a unit weight required for fully winding one bobbin 22 to form a coil. The process then proceeds to step 40.

[0028] In step 40, the winding system 10 begins (or continues) winding. The process then proceeds to step 42.

[0029] In step 42, the controller 12 determines whether the number of completed cycles is equal to the calculated maximum number of winding cycles possible, based on the weight determined in step 32. If the answer is “NO,” then control of the process loops and another winding cycle is performed.

[0030] In an alternate embodiment, controller 12 is configured to generate an alarm a predetermined number of cycles before the maximum number of cycles has been completed (i.e., before the wire runs out) in order to notify the operator that the spindle is low on wire.

[0031] When the maximum number of winding cycles has been completed for that particular spool/spindle, then control of the method passes to step 44.

[0032] In step 44, controller 12 causes the remainder of winding system 10 to discontinue cycling/winding in order to prevent, for example, the whipping of loose ends were a spool of wire to run out in the middle of a winding cycle. At this point, the operator obtains (or perhaps has already obtained, based on an optional alarm) another spool of wire, weighs the spool in accordance with procedure described above, and rethreads the new spool of wire. Rethreading may involve tying the “new” wire to the remaining “old” wire (i.e., on the spool side of the dereeler) and pulling the end of the new wire through the winding system in order to fully thread the machine 10.

[0033] The invention eliminates the disadvantages of running out of wire in the middle of a winding cycle described above in Background. The use of scale 30 having an interface compatible with controller 12 of winding system 10 removes the opportunity for operator error in entering the weight and the spindle number. The operator need only perform work on the machine 10 once for each change of spool (i.e., for each spindle), which is an improvement over various, conventional winding systems. 

1. A method of winding a bobbin to form a coil comprising the step of determining a weight of a spool containing wire and electrically providing said determined weight to a winding system configured to use said determined weight to control winding of said bobbin.
 2. The method of claim 1 further including the step of determining a number of complete winding cycles that can be performed based on said determined weight.
 3. The method of claim 2 further including the step of discontinuing a sequence of complete winding cycles when said spool of wire has been used to wind one or more bobbins over said determined number of complete winding cycles.
 4. The method of claim 2 further including the step of generating an alarm a predetermined number of cycles prior to completing said determined number of complete winding cycles.
 5. The method of claim 1 wherein said step of determining said weight is performed by the substeps of placing the spool on an electronic scale that is electrically coupled to said winding system.
 6. The method of claim 5 wherein said winding system includes a plurality of spindles configured to receive a corresponding plurality of bobbins for winding, said method further including the step of identifying one of said spindles for an operator and soliciting an acceptance of said one identified spindle.
 7. The method of claim 2 wherein said step of determining said number of complete winding cycles is performed in accordance with said determined weight and a unit weight corresponding to an amount of wire wound on a fully wound bobbin.
 8. The method of claim 1 wherein said coil is selected from the group comprising an ignition coil, a stator winding, a motor winding, an insertion winding, a layered winding, a progressive winding, a segment winding, a yoke winding, a bobbin type winding, a paper sectioned winding, a toroidal winding, and a bondable wire type winding.
 9. The method of claim 8 wherein said selected coil is an ignition coil comprising at least one of a primary ignition coil and a secondary ignition coil.
 10. A system for winding a bobbin to form a coil comprising: a scale for generating a weight signal indicative of a weight of a wire spool; a winding system having an input configured to receive said weight signal, said winding system responsive to said weight signal to control winding of said bobbin using wire from said wire spool.
 11. The system of claim 10 wherein said winding system includes a plurality of spindles configured to receive a plurality of bobbins for winding, said winding system having a controller configured to determine a maximum number of complete winding cycles that can be performed using the wire on the wire spool based on said weight signal.
 12. The system of claim 11 wherein said controller is further configured to discontinue a sequence of complete winding cycles when said wire spool of wire has been used to wind one or more coils over said maximum number of complete winding cycles.
 13. The system of claim 12 wherein said controller is further configured to generate an alarm a predetermined number of cycles prior to said maximum number of complete winding cycles.
 14. The system of claim 13 wherein said coil is selected from the group comprising an ignition coil, a stator winding, a motor winding, an insertion winding, a layered winding, a progressive winding, a segment winding, a yoke winding, a bobbin type winding, a paper sectioned winding, a toroidal winding, and a bondable wire type winding.
 15. A method of winding a bobbin to form a coil comprising the steps of: automatically determining a weight of a wire spool containing wire and electronically providing said determined weight to a winding system configured to use said determined weight to control winding of a corresponding bobbin; associating said determined weight with one of a plurality of spindles of said winding system on which said bobbin is received; determining a maximum number of complete winding cycles that can be performed based on said determined weight, each cycle corresponding to a full winding of a bobbin with wire; and discontinuing a sequence of complete winding cycles when the maximum number of complete winding cycles has been completed for associated spindle. 